Electrically operated valve



April 24, 1945. L. E. FLORY ELECTRICALLY OPERATED VALVE Filed April 50,1942 *E I I I' Leslie E. Fli g;

(Ittomeg Patented Apr. 24, 1945 ELECTRICALLY OPERATED VALVE Leslie E.Flory, Oaklyn, N. J assignor to Radio Corporation of America, acorporation of Delaware Application April 30, 1942, Serial No. 441,068

1 Claim.

This invention relates to improvements in vacuum plumbing and has forits principal object to provide an improved cut-ofi valve for use insuch systems.

Another and related object of the present invention is to provide asimple, yet reliable and trouble-free cut-oil valve, and one which mayconveniently be controlled from a remote point.

Still another object of the present invention is to provide an improvedmercury-sealed valve of the general character described, and onecharacterized by the relatively small quantity of mercury required toensure a perfect seal. I

Other objects and advantages together with certain preferred details ofconstruction will be apparent and the invention itself will be bestunderstood by reference to the following specification and to theaccompanying drawing, wherein:

Figure 1 is an elevational view partly in section showing a vacuumplumbing system incorporating the improved remotely controlled cut-offvalve of the present invention, Figure 2 is a fragmentary sectional viewshowing the valve of Fig. 1 in the closed position, Figure 3 is asectional view taken on the line 3-3 of Fig. 1, and Figure 4 is aschematic diagram of a modification of the magnetic actuating system.

In the vacuum plumbing system shown in Figs. 1 to 3, inclusive, ldesignates generally a tube or compartment which will be understood tobe connected to, or to comprise, a device to be evacuated. The part I isconnected as by a pipe 2 to a flow opening 3 in the lower chamber ortrap 4 of a vertically mounted glass cylinder or case 5 whose upper orcut-01f chamber 6 contains a flow opening I which is connected to avacuum 7 pump (not shown) through a pipe 8. The upper and lower chambersof the cylindrical glass case 5 are separated by a glass disc or base 9which serves as a support for a centrally located hollow tube l0 whichhas an upper port Illa at a point beneath the flow opening I in theupper chamber 5 and which extends to a point adjacent to the bottom ofthe lower chamber 4. In agreement with standard practice the lowerchamber 4 may be seated within a receptacle ll containing a filling I!of liquid air or dry ice which serves to condense any vapor which mayenter the trap 4. Obviously, in the absence of any impediment to itsflow, air or other gas will be drawn by the pump from the compartment ordevice I through the pipe 2 and flow opening 3 into the trap 4, thencethrough the central tube I 0 and its port lOa to the upper or cut-ofi"out through the flow opening I to the exhaust pipe 8. t

The upper chamber 6 of the glass case 5 contains a cut-off valvecomprisin an inverted cupshaped member l3 fixed on the lower end of arod-like valve stem I4 and which is adapted, in a manner laterdescribed, to be raised from and lowered into a pool of mercury H) whichis contained in the annular space surrounding the upper end or port Illaof the hollow tube In which connects the cut-off (upper) chamber 6 withthe lower (trap) chamber 4.

It will be observed upon inspection of Figs. 1 and 2 that the valve steml4 has a number (say, three) of upwardly extending outwardly bowedresilient fingers l6 fixed thereon intermediate its ends and that thewall of the glass envelope, above the exhaust port 1 has a constrictionH therein which serves as a latch for holding the valve stem l4 in theraised position when the said fingers are urged upwardly against theforce of their 'bias, beyond the said constriction, as shown inFig.1.

In the embodiment of the invention shown in Fig. 1, magnetic forces orfields are employed for raising and lowering the valve stem assembly.These magnetic forces are supplied by separate coils l8 and I9surrounding the upper end of the glass envelope 5 and are selectivelyapplied to an iron slug or core 2|] on the upper end of the valve steml4 by means of switches 2i and 22 which are in circuit with a commonsource of current exemplified by the battery 23. The magnetic fieldgenerated by the upper coil l8 and applied to the iron slug 20 when theswitch 2| is closed is of suificient intensity to raise the valve stem Mto a position whereat the resilient fingers iii are compressed andpassed beyond the constriction I! in the glass envelope 5. When thevalve is in the raised position, the iron slug 2n is in register withthe upper or lifting coil l8 and is maintained there, against the forcesof gravity, when the switch 2| is opened, by the resilient fingers I6which now rest upon the constricted portion ll of the envelope 5.

From the foregoing it is apparent that in order to lower end valve l3,some positive force must be employed to overcome the biasing force whichmaintains the resilient fingers IS in their expanded position above theconstriction l1. Such a positive force is applied to the iron slug 20 onthe upper end of the valve stem I4 by the coil l9 when the switch 22 isclosed. That is to say, the magnetic field generated by the said coil Hatchamber 6 and then tracts the slug :0 and drives the valve stem l4downwardly with suflicient force to collapse the resilient fingers l8and project them through the constriction I1 whereupon, as shown in Fig.2, the cup-shaped valve l3 enters the pool of mercury I5 and efiectivelycloses the otherwise open end of the tube I0.

Referring to the alternative embodiment of the invention shown in Fig.4: By substituting a permanently magnetized or polarized core 20a forthe iron slug 20 of Fig. 1, it is possible to employ a single actuatingcoil 26 for moving the valve stem assembly in both directions. In thiscase, a double pole double throw switch 21 in the circuit between thecoil 25 and the battery 23a-serves to reverse the current flowing in thecoil when the direction of movement of the valve stem assembly is to bechanged.

In order to prevent undesired tilting or lateral movement of the valvel3, it may be provided on its outer surface with a number of radiallyextending fins or spokes 24 which slidably engage the inner wall of thecut-off chamber.

The quantity of mercury required to ensure a perfect cut-oil action inany given installation may be readily ascertained by reference to themaximum pressure difference to which this sealing fluid may besubjected. Thus, if subsequent to its evacuation, the device is to beprovided with a filling of gas (which may be supplied thereto when thevalve I3 is closed, through a stop cock 25 in the pipe 2) at a. pressureof, say, 2 mm, of mercury, then, referring to Fig. 2, the difierencebetween the level of the mercury inside and outside the cup l3occasioned by the said difference in pressure, will be 2 mm. It is thunecessary to provide merely sufficient additional mercury (say, a fewcubic centimeters) to prevent the gas from being drawn under theperiphery of the cup in the presence of the difierence (2 mm.) in theinside and outside levels of mercury.

From the foregoing it will be apparent that the present inventionprovides an improved remotely controlled, magneticall actuated,mercury-scaled valve and one characterized by its simple constructionand trouble-free performance.

What is claimed is:

A vacuum plumbing system comprising a glass valve chamber having a longvertical axis and containing a valve port adjacent to its lower end anda constriction in a wall of said chamber intermediate its ends, a valvestem mounted for movement along said axis entirely within said chamber,a closure element for said port mounted on the lower end of said valvestem beneath said constriction, magnetic core means mounted on the upperend of said valve stem above said c0nstriction, a plurality of upwardlyextending, outwardly biased resilient fingers mounted on said valve stemintermediate said closure element and said core means, said resilientfingers being adapted to be compressed and passed through saidconstriction upon movement of said valve stem, and upon cessation ofsaid movement to retain said valve stem and hence said closure elementin the raised or in the lowered position with respect to said port asdetermined by the direction of said movement, and magnetic coil meansmounted about the upper end of said vertical axi exterior of saidchamber for raising and lowering said core means and hence said valvestem and closure element against the retaining force of said resili' entmeans.

LESLIE E. FLORY.

